“My prayers are with Jo and I hope she is okay,” Mr Barwell told the Press Association.

“It is an unavoidable part of the job that we meet constituents in lots of unsecured locations - on the streets, fairs, meetings.

“Unless you sort of lock MPs away from the public, which would be a terrible ting for our democracy, you can’t remove the threat unfortunately.

“All you can do is take sensible advice and make sure your office is as safe as possible.”

Shadow policing minister Jack Dromey told BBC News: “We’ve had in the past serious attacks on MPs, for example my dear friend Stephen, and then additional security measures were taken, and I think fresh security guidance might now be necessary at the next stages.

“But that is for the next stages. For today our thoughts are with Jo.”

Mr Dromey said he intended to continue with his planned surgeries.

He said: “The very last thing that can happen is for us to be intimidated from doing our job. The public expect us to be out there on their behalf.

“I have got a surgery - one on Friday, one on Saturday - and I will be there and of course we are talking to the local police about any sensible security measures that might be taken, but what we cannot allow to happen is for savagery of this kind to stop the democratic process of members of parliament doing their job because that is what the people expect.”